# MCQs For NCERT Class 11 Physics Chapter 9 Mechanical Properties of Solids

Please refer to the MCQ Questions for Class 11 Physics Chapter 9 Mechanical Properties of Solids with Answers. The following Mechanical Properties of Solids Class 11 Physics MCQ Questions have been designed based on the latest syllabus and examination pattern for Class 11. Our experts have designed MCQ Questions for Class 11 Physics with Answers for all chapters in your NCERT Class 11 Physics book.

## Mechanical Properties of Solids Class 11 MCQ Questions with Answers

See below Mechanical Properties of Solids Class 11 Physics MCQ Questions, solve the questions and compare your answers with the solutions provided below.

Question. A steel wire of length 20 cm and uniform cross-section 1 mm2 is tied rigidly at both the ends. The temperature of the wire is altered from 40ºC to 20ºC. Coefficient of linear expansion for steel a = 1.1 × 10–5/ºC and Y for steel is 2.0 × 1011 N/m2. The change in tension of the wire is
(a) 2.2 × 106 newton
(b) 16 newton
(c) 8 newton
(d) 44 newton

D

Question. A cube is subjected to a uniform volume compression. If the side of the cube decreases by 2% the bulk strain is
(a) 0.02
(b) 0.03
(c) 0.04
(d) 0.06

D

Question. A wire suspended vertically from one of its ends is stretched by attaching a weight of 200N to the lower end. The weight stretches the wire by 1 mm. Then the elastic energy stored in the wire is
(a) 0.2 J
(b) 10 J
(c) 20 J
(d) 0.1 J

D

Question. A metal rod of Young’s modulus 2 × 1010 N m–2 undergoes an elastic strain of 0.06%. The energy per unit volume stored in J m–3 is
(a) 3600
(b) 7200
(c) 10800
(d) 14400

A

Question. A force of 103 newton, stretches the length of a hanging wire by 1 millimetre. The force required to stretch a wire of same material and length but having four times the diameter by 1 millimetre is
(a) 4 × 103 N
(b) 16 × 103 N
(c) 1/4 x 103 N
(d) 1/16 x 103N

B

Question. Which one of the following is not a unit of Young’s modulus ?
(a) Nm–1
(b) Nm–2
(d) dyne cm–2
(d) mega pascal

A

Question. Two rods A and B of the same material and length have their radii r1 and r2 respectively. When they are rigidly fixed at one end and twisted by the same couple applied at the other end, the ratio  (Angle of twist at the end of A / Angle of twist at the end of B ) is
(a) r12 / r22
(b) r13 / r23
(c) r24 / r14
(d) r14 / r24

C

Question. A 2 m long rod of radius 1 cm which is fixed from one end is given a twist of 0.8 radian. The shear strain developed will be
(a) 0.002
(b) 0.004
(c) 0.008
(d) 0.016

B

Question. The approximate depth of an ocean is 2700 m. The compressibility of water is 45.4 × 10–11 Pa–1 and density of water is 103 kg/m3.What fractional compression of water will be obtained at the bottom of the ocean ?
(a) 1.0 × 10–2
(b) 1.2 × 10–2
(c) 1.4 × 10–2
(d) 0.8 × 10–2

B

Question. The Young’s modulus of steel is twice that of brass. Two wires of same length and of same area of cross section, one of steel and another of brass are suspended from the same roof. If we want the lower ends of the wires to be at the same level, then the weights added to the steel and brass wires must be in the ratio of :
(a) 2 : 1
(b) 4 : 1
(c) 1 : 1
(d) 1 : 2

A

Question. The bulk modulus of a spherical object is ‘B’. If it is subjected to uniform pressure ‘p’, the fractional decrease in radius is
(a) B /3p
(b) 3p /B
(c) p /3B
(d) p /B

C

Question. There are two wire of same material and same length while the diameter of second wire is two times the diameter of first wire, then the ratio of extension produced in the wires by applying same load will be
(a) 1 : 1
(b) 2 : 1
(c) 1 : 2
(d) 4 : 1

D

Question. For a given material, the Young’s modulus is 2. 4 times that of rigidity modulus. Its Poisson’s ratio is
(a) 2.4
(b) 1.2
(c) 0.4
(d) 0.2

D

Question. A cube at temperature 0ºC is compressed equally from all sides by an external pressure P. By what amount should its temperature be raised to bring it back to the size it had before the external pressure was applied. The bulk modulus of the material of the cube is B and the coefficient of linear expansion is a.
(a) P/B a
(b) P/3 B a
(c) 3 p a/B
(d) 3 B/P

B

Question. The compressibility of water is 4 × 10–5 per unit atmospheric pressure. The decrease in volume of 100 cm3 of water under a pressure of 100 atmosphere will be
(a) 0.4 cm3
(b) 4 × 10–5 cm3
(c) 0.025 cm3
(d) 0.004 cm3

A

Question. For the same cross-sectional area and for a given load, the ratio of depressions for the beam of a square cross-section and circular cross-section is
(a) 3 : π
(b) π : 3
(c) 1 : π
(d) π : 1

A

Question. A massive stone pillar 20 m high and of uniform crosssection rests on a rigid base and supports a vertical load of 5.0 × 105 N at its upper end. If the compressive stress in the pillar is not to exceed 1.6 × 106 N m–2, what is the minimum cross-sectional area of the pillar? Density of the stone
= 2.5 × 103 kg m–3. (Take g = 10 N kg–1)
(a) 0.15 m2
(b) 0.25 m2
(c) 0.35 m2
(d) 0.45 m2

D

Question. A circular tube of mean radius 8 cm and thickness 0.04 cm is melted up and recast into a solid rod of the same length. The ratio of the torsional rigidities of the circular tube and the solid rod is
(a) (8.02)4 – (7.98)4 /(0.8)4
(b) (8.02)4 – (7.98)4 / (0.8)2
(c) (0.8)2 / (8.02)4 – (7.98)4
(d) (0.8)2 / (8.02)3 – (7.98)2

A

Question. From a steel wire of density r is suspended a brass block of density rb. The extension of steel wire comes to e. If the brass block is now fully immersed in a liquid of density rl, the extension becomes e’. The ratio e’/e will be
(a) Ρb /Ρb -Ρl
(b) Ρb -Ρ/Ρb
(c) Ρb -Ρ / Ρl – Ρ
(d) Ρl /Ρb –l

A

Question. One end of a uniform wire of length L and of weight W is attached rigidly to a point in the roof and W1 weight is suspended from looser end. If A is area of cross-section of the wire, the stress in the wire at a height L/4 from the upper end is
(a) W1 + W /a
(b) W1 + 3W / 4 /a
(c) W1 + W/4 /a
(d) 4W1 + 3W /a

B

Question. A beam of metal supported at the two edges is loaded at the centre. The depression at the centre is proportional to
(a) Y 2
(b) Y
(c) 1/Y
(d) 1/Y 2

C

Question. An iron rod of length 2m and cross-sectional area of 50 mm2 stretched by 0.5 mm, when a mass of 250 kg is hung from its lower end. Young’s modulus of iron rod is
(a) 19.6´1020 N/m2
(b) 19.6´1018 N/m2
(c) 19.6´1010 N/m2
(d) 19.6´1015 N/m2

C

Question. A wire fixed at the upper end stretches by length l by applying a force F. The work done in stretching is
(a) 2Fl
(b) Fl
(c) F/2l
(d) Fl /2

D

Question. A metalic rod of length l and cross-sectional area A is made of a material of Young modulus Y. If the rod is elongated by an amount y, then the work done is proportional to
(a) y
(b) 1/y
(c) y2
(d) 1/y2

C

Question. On stretching a wire, the elastic energy stored per unit volume is
(a) Fl/2AL
(b) FA/2L
(c) FL/2A
(d) FL/2

A

Question. If a rubber ball is taken at the depth of 200 m in a pool, its volume decreases by 0.1%. If the density of the water is 1 × 103 kg/m3 and g = 10m/s2, then the volume elasticity in N/m2 will be
(a) 108
(b) 2 × 108
(c) 109
(d) 2 × 109

D

Question. A material has poisson’s ratio 0.50. If a uniform rod of it suffers a longitudinal strain of 2 × 10–3, then the percentage change in volume is
(a) 0.6
(b) 0.4
(c) 0.2
(d) Zero

D

Question. A 5 metre long wire is fixed to the ceiling. A weight of 10 kg is hung at the lower end and is 1 metre above the floor. The wire was elongated by 1 mm. The energy stored in the wire due to stretching is
(a) zero
(b) 0.05 joule
(c) 100 joule
(d) 500 joule

B

Question. Two wires A and B are of the same material. Their lengths are in the ratio of 1 : 2 and the diameter are in the ratio 2 : 1. If they are pulled by the same force, then increase in length will be in the ratio of
(a) 2 : 1
(b) 1 : 4
(c) 1 : 8
(d) 8 : 1